Shore-Originated Call - Furuno FELCOM 12 Service Manual

2. Shore-originated Call

The following describes how a subscriber to the public telecommunications networks can
send a message to an MES.
Tunes to NCS CC
Receives update on BB and
tunes to CES TDM channel.
And decodes BB & SCD.
Tunes to SES
signalling channel
Message Reception
Tunes to CES TDM
channel
Receives all messages
and finds packets in
error.
Tunes to SES signalling
channel
Tunes to CES TDM
Re-tunes to NCS CC
SCD) Signal Channel Descriptor Packet
ISL) Interstation Signalling Link
BB) Bulletin Board
Call
Terrestrial
subscriber
Message
MES
NCS CC
(Announcement)
SES Signalling Channel
(Assignment Response)
CES TDM
(Message)
CES TDM
(Acknowledgement Request)
SES Signalling Channel
(Acknowledgement)
CES TDM
(Clear)
NCS CC
LES
Check if MES is logged-in.
Stores all message.
ISL
(MES Status Request
+ Announcement)
(MES Status)
ISL
(MES Status : Announcing)
ISL
(MES Status: busy)
Retransmits any packets
received by MES in error.
After 60 sec.
ISL
(MES Status : idle)
END
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NCS
Check of MES status.
• not in the region
• Idle
• Busy
When MES is idle.
NCS updates data on this MES
to busy.
NCS updates data base.
(MES status changed to idle)